Adriana Gamboa Earns 2019 ASCO Merit Award

November 2018

General surgery resident Adriana Gamboa, MD, who is engaged in a two-year research sabbatical in the lab of Shishir Maithel, MD, received a 2019 Conquer Cancer Foundation Merit Award from the American Society of Clinical Oncology. This is the fifth year in a row that a resident working in Dr. Maithel's lab has been recognized with a Merit Award.

The award will assist with funding Dr. Gamboa's attendance of the 2019 Gastrointestinal Cancers Symposium in San Francisco, January 17-19, where she will present "Duodenal neuroendocrine tumors: Somewhere between the pancreas and small bowel?"

Pancreatic neuroendocrine tumors (NETs) smaller than 2 cm are typically observed rather than removed, while small bowel NETs are routinely resected in tandem with a regional lymphadenectomy regardless of size because of their malignant potential.

Given this variability, Dr. Gamboa and her coauthors sought to define the natural history of duodenal neuroendocrine tumors (D-NETs) and the general protocol for resection when they are encountered, as well as to document the types of symptoms and range of lab results associated with overall survival in patients who undergo resection.

Patients from the National Cancer Database that were diagnosed with non-metastatic, non-functional D-NETs from 2004-2014 were included in the study. Local resection was defined as local excision, polypectomy, or excisional biopsy, while anatomic resection was defined as removal with radical surgery.

Tumor size was divided into three categories (<1 cm, 1-2 cm, ≥2 cm). Propensity score weighting analysis was used to create balanced cohorts between resection and non-resection patients and was maintained in all three sizes. The primary endpoint was overall survival.

The median age of the 5,502 patients in the study was 65, and 52% were male. Median follow-up was 51 months, and median tumor size was 0.8 cm. Resection was performed in 72% of patients (n=3,954), of which 61% had local resection, and 39% had anatomic resection. At least one lymph node (LN) was retrieved in 25% of patients, 44% of whom had LN metastasis. Seventy four % had negative margins.

Resection was associated with improved median overall survival compared to non-resection for all three sizes. Subset analysis of each size cohort who underwent resection demonstrated that neither type of resection, LN retrieval, LN positivity, or margin status was associated with overall survival.

Dr. Gamboa and her team concluded that all patients with non-metastatic, non-functional D-NETs should be considered for resection regardless of tumor size, and that the type of resection and extent of LN retrieval should be tailored to the patient's clinical status and safety profile, particularly in light of the LNs lack of prognostic value.

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